CN105371879A - Absolute encoder and surveying device - Google Patents

Absolute encoder and surveying device Download PDF

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Publication number
CN105371879A
CN105371879A CN201510477260.2A CN201510477260A CN105371879A CN 105371879 A CN105371879 A CN 105371879A CN 201510477260 A CN201510477260 A CN 201510477260A CN 105371879 A CN105371879 A CN 105371879A
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China
Prior art keywords
mentioned
light
absolute type
type encoder
index dial
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Granted
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CN201510477260.2A
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Chinese (zh)
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CN105371879B (en
Inventor
弥延聪
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Topcon Corp
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Topcon Corp
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C1/00—Measuring angles
    • G01C1/02—Theodolites
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/244—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
    • G01D5/24428—Error prevention
    • G01D5/24433—Error prevention by mechanical means
    • G01D5/24438—Special design of the sensing element or scale
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/347—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells using displacement encoding scales
    • G01D5/34707—Scales; Discs, e.g. fixation, fabrication, compensation
    • G01D5/34715—Scale reading or illumination devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/347—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells using displacement encoding scales
    • G01D5/3473—Circular or rotary encoders
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/347—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells using displacement encoding scales
    • G01D5/34776—Absolute encoders with analogue or digital scales

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Optical Transform (AREA)

Abstract

An absolute encoder includes a light-emitting mechanism including a light-emitting surface and emitting detection light from the light-emitting surface. A light-receiving mechanism including a scale plate having a scale area and receiving at a light-receiving area the detection light emitted from the light-emitting surface and passing through the scale area of the scale plate. The light-emitting mechanism and the light-receiving mechanism are set to a positional relationship that inclines an irradiation axis extending from the light-emitting surface through the scale area to the light-receiving area relative to a rotation axis direction of the scale plate.

Description

Absolute type encoder and measurement mechanism
Technical field
The present invention relates to the measurement mechanism of absolute type encoder and the above-mentioned absolute type encoder of lift-launch utilized by the detection light of the scale zone of index dial.
Background technology
In the measurement mechanism for measuring, have the measurement mechanism utilizing absolute type encoder to come detection level angle, vertical angle.In above-mentioned absolute type encoder, utilize the scale zone irradiating index dial from the detection light of lighting means injection, utilize light authorities by the detection light of above-mentioned scale zone, and the rotation attitude of index dial is obtained according to the detected value based on this light, detection level angle, vertical angle (for example, referring to patent documentation 1) accordingly.
But, in absolute type encoder, by the light area in optical mechanism, there is reflectivity.For this reason, there is following situation, namely in absolute type encoder, the part of detection light of irradiating light area reflects towards index dial, and this is by the detection light that reflects secondary reflection and arrive light area again on index dial.Above-mentionedly hindered by the detection light reflected the detection light received rightly in light area (by optical mechanism) by scale zone, thus make cannot obtain appropriate detected value by optical mechanism.As a result, in absolute type encoder, the rotation attitude of index dial can not be obtained rightly, thus make the accuracy of detection decline at horizontal angle, vertical angle.
For this reason, in absolute type encoder, consider and antireflection film is set at the back side (face of side, light area) of index dial.In such an embodiment, even if when a part for the detection light irradiating light area reflects towards index dial, also can prevent here by the detection light that reflects secondary reflection again on index dial (its back side), and can prevent the detection light reflected from can arrive light area.
(prior art document)
(patent documentation)
Patent documentation 1: Japanese Unexamined Patent Publication 2002-13949 publication
Summary of the invention
But, in absolute type encoder, if arrange antireflection film at the back side of index dial, then can increase manufacturing process, and required material can be increased, thus manufacturing cost is improved.
The present invention proposes in view of above-mentioned item, its object is to provide a kind of and suppresses the increase of manufacturing cost and prevent the absolute type encoder of the decline of the angle accuracy of detection caused by the reflection of the detection light between light area and index dial.
In order to reach above-mentioned purpose, the absolute type encoder of one embodiment of the present of invention possesses: lighting means, for from exit facet irradiating and detecting light; And by optical mechanism, utilize light area to receive from the injection of above-mentioned exit facet and the above-mentioned detection light of scale zone by index dial, above-mentioned lighting means and above-mentioned light mechanism sets to become to make from above-mentioned exit facet through above-mentioned scale zone towards the position relationship that the irradiation axis of above-mentioned light area tilts relative to the rotation direction of above-mentioned index dial.
Accompanying drawing explanation
Fig. 1 is the key diagram of the structure of the measurement mechanism of the embodiment of the example schematically shown as measurement mechanism of the present invention.
Fig. 2 is the key diagram of the structure schematically showing the absolute type encoder being equipped on measurement mechanism.
Fig. 3 is the key diagram being shown schematically in two groups of lighting means in each absolute type encoder and clipping index dial and paired state by optical mechanism.
Fig. 4 be illustrate from lighting means injection light through index dial (its slit) by the key diagram of the state of light authorities.
Fig. 5 illustrates the figure being subject to an example of light signal as the numeral represented by the Digital Image Data of the light content in optical mechanism, represents the longitudinal axis, and represent transverse axis with pixel number with digital level value.
Fig. 6 illustrates the figure of the numeral corresponding with the slit of 1 in Fig. 5 by an example of light signal, represents the longitudinal axis, and represent transverse axis with pixel number with digital level value.
Fig. 7 is for illustration of clipping the key diagram of the paired lighting means of index dial with the position relationship by optical mechanism.
Fig. 8 be with the mode of partial enlargement illustrate from lighting means (its exit facet) detection light L by the face that comprises rotation direction and light axis direction and through the scale zone (each slit) of index dial in the state of the light area light by optical mechanism and reflect and detect the key diagram of light in the state of light area light.
Fig. 9 illustrates that the numeral as the Digital Image Data representing the light content be subject in optical mechanism is subject to a numeral when example of light signal and reception reflection detection light to be subject to the figure of an example of light signal, represent the longitudinal axis with digital level value, and represent transverse axis with pixel number.
In the mode of partial enlargement, Figure 10 illustrates that detection light L from lighting means (its exit facet) is by comprise on rotation direction and the face of light axis direction and to detect in the state of the light area light by optical mechanism and reflection the key diagram identical with Fig. 8 that light does not arrive the state of light area through the scale zone (each slit) of index dial.
Figure 11 is for illustration of irradiating axis relative to the key diagram of establishing method of the degree of tilt in the face comprising rotation direction and light axis direction.
Figure 12 is for illustration of irradiating axis relative to comprising rotation direction and the key diagram identical with Figure 11 of the establishing method of the degree of tilt in the face of light axis direction in the absolute type encoder of embodiment 2.
Figure 13 is for illustration of irradiating axis relative to comprising rotation direction and the key diagram identical with Figure 11 of the establishing method of the degree of tilt in the face of light axis direction in the absolute type encoder of embodiment 3.
Figure 14 is for illustration of irradiating axis relative to comprising rotation direction and the key diagram identical with Figure 11 of the establishing method of the degree of tilt in the face of light axis direction in the absolute type encoder of embodiment 4.
Figure 15 is the key diagram of the structure of absolute type encoder for illustration of embodiment 5.
Figure 16 is the key diagram identical with Figure 15 of the structure of absolute type encoder for illustration of embodiment 6.
Figure 17 is the key diagram identical with Figure 15 of the structure of absolute type encoder for illustration of embodiment 7.
Embodiment
Hereinafter, with reference to the accompanying drawings of the embodiment of absolute type encoder of the present invention with the measurement mechanism of the above-mentioned absolute type encoder of lift-launch.
(embodiment 1)
First, the brief configuration of the measurement mechanism 10 of the lift-launch absolute type encoder 30 of embodiments of the invention 1 is described.As shown in Figure 1, in embodiment 1, above-mentioned measurement mechanism 10 is total powerstation, can towards measurement point irradiated with pulse laser light, and reception is found range for each pulse from the pulse-echo light of above-mentioned measurement point, and range measurement is averaged and carries out high-precision range observation.Above-mentioned measurement mechanism 10 has leveling portion 11, basal disc portion 12, bracket part 13 and telescope part 14.
Leveling portion 11 is installed on tripod 15, can detect the inclination of measurement mechanism 10 (telescope part 14).Basal disc portion 12 is arranged at leveling portion 11 to change relative to the mode at the pitch angle in above-mentioned leveling portion 11.Bracket part 13 is arranged at basal disc portion 12 in the mode that can rotate (rotating around vertical axis Av) with vertical axis Av for rotation center relative to basal disc portion 12.Above-mentioned bracket part 13 is provided with display part 16 and operation inputting part 17.Aforesaid operations input part 17 is the operating portion of the various functions for utilizing measurement mechanism 10, to the information of the operation that following control module 22 (with reference to Fig. 2) inputs.Display part 16 shows and is used for utilizing the operation screen of various function or measurement result etc. according to the operation performed in operation inputting part 17 under the control of control module 22.
Telescope part 14 is opposing brackets portion 13 mode of carrying out rotating (rotating around horizontal axis Ah) for rotation center with horizontal axis Ah can be arranged at bracket part 13.Telescope part 14 is provided with the foresight sight 18 in the roughly collimation direction for setting measurement device 10.Telescope part 14 has the second telescope 19 and the first telescope 21, and above-mentioned second telescope 19 pairs of measuring object things carry out collimation, and above-mentioned first telescope 21 has the multiplying power lower than above-mentioned second telescope 19 and wide-angle view.The first shoot part and the second shoot part is provided with in above-mentioned telescope part 14, above-mentioned first shoot part obtains the image (wide angle picture) in collimation direction or roughly collimation direction via the optical system of the first telescope 21, and above-mentioned second shoot part obtains the image (image of looking in the distance) in collimation direction via the optical system of the second telescope 19.In addition, be built-in with the ranging unit of the optical system of shared second telescope 19 at telescope part 14, the light wave distance measuring that injection range finding light also receives the reflected light from measuring object thing and proceeds to till measuring object thing.
In above-mentioned measurement mechanism 10, as mentioned above, telescope part 14 supports to and can rotate around horizontal axis Ah by bracket part 13, and bracket part 13 can rotate around vertical axis Av relative to basal disc portion 12.For this reason, telescope part 14 can rotate, namely rotate in the horizontal direction around vertical axis Av, and can rotate, namely rotate in vertical around horizontal axis Ah.In measurement mechanism 10, under the control of following control module 22 (with reference to Fig. 2), telescope part 14 suitably can rotate around vertical axis Av (horizontal direction), and telescope part 14 suitably can rotate around horizontal axis Ah (vertical).In measurement mechanism 10, in order to detect telescope part 14 around the anglec of rotation of vertical axis Av (horizontal direction) and the anglec of rotation around horizontal axis Ah (vertical) of telescope part 14, be provided with absolute type encoder 30 (with reference to Fig. 2).Relevant above-mentioned absolute type encoder 30, describes in detail in further part.
The control module 22 (with reference to Fig. 2) of the action for being all together ground control and measure device 10 is built-in with in bracket part 13.The driving of control module 22 level of control drive division and vertical drive division makes bracket part 13 and telescope part 14 suitably rotate, and above-mentioned telescope part 14 can be made accordingly towards the direction of regulation, and the scope of scanning regulation.Control module 22 is while control the switching of the first telescope 21 and the second telescope 19, suitably control the first above-mentioned shoot part and the second shoot part on one side, the image of desired multiplying power can be obtained accordingly, and control above-mentioned ranging unit and the range finding of the measurement point specified can be carried out.Control module 22, from absolute type encoder 30 receiving angle detection signal, can obtain horizontal angle and the vertical angle of telescope part 14 (its collimation direction) accordingly.For this reason, in measurement mechanism 10, leveling portion 11, basal disc portion 12, bracket part 13, telescope part 14, foresight sight 18, second telescope 19, first telescope 21 and absolute type encoder 30 (with reference to Fig. 2) play a role as the measuring unit by control module 22 drived control.
In measurement mechanism 10, be provided with 2 absolute type encoders 30.In more detail, as shown in Figure 2, an absolute type encoder 30 is for detecting the scrambler of telescope part 14 around the anglec of rotation of vertical axis Av (horizontal direction), and another absolute type encoder 30 is for detecting the scrambler of telescope part 14 around the anglec of rotation of horizontal axis Ah (vertical).An absolute type encoder 30 detects the anglec of rotation of the horizontal direction in the basal disc portion 12 relative to bracket part 13, i.e. feathering angle, detect the anglec of rotation around vertical axis Av (horizontal direction) of (measurement of angle) telescope part 14 accordingly, i.e. the horizontal angle in the collimation direction of telescope part 14.Another absolute type encoder 30 detects the anglec of rotation of the vertical of the bracket part 13 relative to telescope part 14, i.e. vertical rotation angle, detect the anglec of rotation around horizontal axis Ah (vertical) of (measurement of angle) telescope part 14 accordingly, i.e. the vertical angle in the collimation direction of telescope part 14.Above-mentioned each absolute type encoder 30 makes except configuration relation difference except the difference according to detection angles (horizontal angle or vertical angle), mutually the same structure is adopted to carry out identical action, thus for same section, mark identical Reference numeral to illustrate.
In each absolute type encoder 30, by lighting means 32 with by optical mechanism 33, to be arranged to clip index dial 31 paired.In addition, in each absolute type encoder 30, adopt above-mentioned lighting means 32 and form with the setting position of the rotation center relative to index dial 31 the opposed detection architecture that rotational symmetric mode is provided with two groups by the combination (testing agency) of optical mechanism 33.For this reason, in measurement mechanism 10, in order to detection level angle, being provided with 1 index dial, 31,2 lighting means 32 and 2 by optical mechanism 33, in order to detect vertical angle, being provided with 1 index dial, 31,2 lighting means 32 and 2 by optical mechanism 33.In above-mentioned each absolute type encoder 30, index dial 31, paired lighting means 32 are arranged in the mode that can relatively rotate with by optical mechanism 33.In each absolute type encoder 30, in embodiment 1, index dial 31 rotates relative to paired lighting means 32 with by optical mechanism 33.Namely, index dial 31 is arranged to rotate relative to the rotation of the horizontal direction in basal disc portion 12 with bracket part 13 in an absolute type encoder 30, and index dial 31 is arranged to rotate relative to the rotation of the vertical of bracket part 13 with telescope part 14 in another absolute type encoder 30.Below, parallel direction, the direction that extended by the rotation of the index dial 31 with 2 absolute type encoders 30 (be vertical axis Av in an absolute type encoder 30, be horizontal axis Ah in another absolute type encoder 30) is as rotation direction Da.
As shown in Figure 3, index dial 31 is configured to overall in disc-shape, and in the edge, periphery of above-mentioned index dial 31, circumferentially (relative sense of rotation) is provided with slit 34 as multiple scale using the interval specified (spacing).Each slit 34 is as described below form the detection light L (with reference to Fig. 4 etc.) that allows to penetrate from lighting means 32 through position, in embodiment 1, the slit that the width dimensions observed in a circumferential direction is large and the little slit of width dimensions alternately arrange and are formed.State as follows more, each slit 34 be formed as when utilize by optical mechanism 33 receive through detection light L (with reference to Fig. 4 etc.) time, the simulation based on the amount of a line (1line) of the light in the whole region throughout following light area 33a (with reference to Fig. 8 etc.) is all inconsistent by light signal Ia (simulated image data) with the simulation of the amount of a line of other the position observed in a circumferential direction by light signal Ia (with reference to Fig. 2) (simulated image data).For this reason, in index dial 31, the region being circumferentially provided with the band shape of above-mentioned each slit 34 becomes the scale zone 35 of the scale (each slit 34) of the rotation attitude be provided with for detecting index dial 31.In embodiment 1, above-mentioned index dial 31 is formed by the following method, namely carry out chromium plating to prevent overall through light (detecting light L (with reference to Fig. 4 etc.)) to the glass plate of disc-shape, and utilize etching etc. to remove chromium plating partly, each slit 34 (with reference to Fig. 4 etc.) is set accordingly.
Lighting means 32 and by optical mechanism 33 with the mode of the scale zone 35 (being provided with the position of each slit 34) clipping index dial 31 opposed arrange.As shown in Figure 4, above-mentioned lighting means 32 is under the control of following control gear 37 (with reference to Fig. 2), and the scale zone 35 towards index dial 31 is penetrated and detected light L.In embodiment 1, lighting means 32 uses light emitting diode to form.For this reason, in embodiment 1, the exit facet 36 that the light-emitting area (exit facet) of above-mentioned light emitting diode (lighting means 32) detects light L as injection in lighting means 32 plays a role.
By optical mechanism 33 under the control of following control gear 37, utilize the detection light L of the scale zone 35 (each slit 34) of light area 33a (with reference to Fig. 8 etc.) reception from lighting means 32 (exit facet 36) injection (irradiation) and through index dial 31, and export the simulation corresponding with light income to control gear 37 by light signal Ia (with reference to Fig. 2).For making multiple photo detector be arranged in, straight line has the one dimension solid-state image pickup element (linear imaging sensor) of the light area 33a (with reference to Fig. 8 etc.) of linearity by optical mechanism 33.Below, the direction (direction of photo detector line spread) extended by above-mentioned light area 33a (by optical mechanism 33) is as light axis direction Dp.Be arranged to make light axis direction Dp be positioned at the direction parallel with the string of disc-shape for the index dial 31 of disc-shape by optical mechanism 33.
In embodiment 1, the above-mentioned optical mechanism 33 that is subject to uses complementary metal oxide semiconductor (CMOS) (CMOS, ComplementaryMetalOxideSemiconductor) imageing sensor to form.By in optical mechanism 33, be made up of 2000 photo detector line spread, light area 33a (with reference to Fig. 8 etc.) is made up of 2000 pixels of line spread, exports the simulation of the amount of 2000 pixels by light signal Ia.In embodiment 1, above-mentioned have the position relationship that can receive the detection light L through the slit of 60 in scale zone 35 34 in the light area 33a (with reference to Fig. 8 etc.) of the amount 2000 pixels by optical mechanism 33.
In each absolute type encoder 30, if penetrate (irradiation) from lighting means 32 to detect light L, detection light L then through each slit 34 of the scale zone 35 of index dial 31 arrives by optical mechanism 33, is not arranging the position of each slit 34, detects light L and does not arrive by optical mechanism 33.For this reason, be subject in optical mechanism 33, the whole region of the light area 33a formed at multiple (being 2000 the in embodiment 1) photo detector (pixel) being configured to line spread obtains simulation by light signal Ia (with reference to Fig. 2), the image of the scale zone 35 (each slit 34) of the position corresponding with the rotation attitude of index dial 31 can be obtained as simulated image data accordingly.That is, by optical mechanism 33, the simulation of the amount of a line from each photo detector (pixel) is processed in batches by light signal Ia, form the simulated image data of the image of each slit 34 of the scale as index dial 31 read accordingly.In embodiment 1, simulated image data is the data receiving the detection light L of each slit 34 of the scale zone 35 through index dial 31 by optical mechanism 33, thus draws the waveform corresponding with each slit 34.The above-mentioned simulation being subject to optical mechanism 33 to export the amount of the multiple pixels as detected value to control gear 37 is by light signal Ia (with reference to Fig. 2).
Control gear 37 controls the action of each absolute type encoder 30 with being all together, and has the function according to carrying out the rotation attitude of computing scale dish 31 from the detected value (simulation is by light signal Ia) respectively by optical mechanism 33.In control gear 37, as shown in Figure 2, from respectively inputting detected value (simulation is by light signal Ia) by optical mechanism 33, and carry out modulus (AD) conversion after interference (noise) etc. is amplified/is removed to simulation by light signal Ia and generate numeral by light signal Id (reference Fig. 5 etc.), and the digital rotation attitude detecting index dial 31 by light signal Id of utilization.Above-mentioned numeral represents the output valve (with reference to Fig. 5) of each pixel in the GTG of digital level value 0 ~ 255 by light signal Id.Numeral is the signal simulation of formation simulated image data being carried out AD conversion by light signal Ia by light signal Id, therefore the amount (the whole region of light area 33a) of a line from each photo detector (pixel) is processed in batches, be formed as the Digital Image Data of drawing the waveform corresponding with each slit 34 of scale zone 35 accordingly.Here, be subject in optical mechanism 33, as mentioned above, the detection light L (with reference to Fig. 4 etc.) through 60 slits 34 can be received in the light area 33a formed by 2000 pixels, thus, in Digital Image Data (simulated image data too), there is the waveform with 60 wave crest portions.
In control gear 37 (with reference to Fig. 2), as shown in Figure 6, center C and the width dimensions W of each wave crest portions of Digital Image Data (numeral of the amount of a line is by light signal Id) is calculated.Normally used various method can be used to carry out calculating central position C and width dimensions W, and thus description is omitted.In control gear 37, ask in the form by the multiple slits 34 obtained in optical mechanism 33 according to the center C of each wave crest portions so calculated and width dimensions W, detect the rotation attitude of index dial 31 accordingly.Also normally used various method can be used to ask for the form of above-mentioned multiple slit 34 and to detect the rotation attitude of index dial 31, and thus description is omitted.In each absolute type encoder 30, be provided with two groups by optical mechanism 33, thus according to the rotation attitude detecting index dial 31 from two groups of outputs by optical mechanism 33, the angle metrical error that the axle that results from above-mentioned index dial 31 rocks can be eliminated accordingly, with the rotation attitude of high precision test index dial 31.
Thus, in an absolute type encoder 30, according to the rotation attitude detecting corresponding index dial 31 from two groups of outputs by optical mechanism 33, the horizontal angle in the collimation direction of (measurement of angle) telescope part 14 can be detected accordingly.In another absolute type encoder 30, according to the rotation attitude detecting corresponding index dial 31 from two groups of outputs by optical mechanism 33, the vertical angle in the collimation direction of (measurement of angle) telescope part 14 can be detected accordingly.
Then, Fig. 7 to Figure 11 is mainly utilized to illustrate the characteristic structural of the absolute type encoder 30 of embodiments of the invention.Fig. 7 is the key diagram for illustration of clipping the paired lighting means of index dial 31 32 and the position relationship by optical mechanism 33, on the radial direction at index dial 31, the center of the scale zone 35 (each slit 34) that Dr observes is as origin position, and is expressed as three-dimensional cartesian coordinate system with mutually orthogonal rotation direction Da together with light axis direction Dp.In the figure 7, using the positive side of the outer circumferential side of index dial 31 as radial direction Dr, and using lighting means 32 relative to the positive side of the side residing for index dial 31 as rotation direction Da.In addition, in order to easy understand lighting means 32 and the position relationship by optical mechanism 33, illustrate by optical mechanism 33 in the mode reducing the length dimension on the Da of rotation direction in Fig. 7, and in the mode only schematically showing scale zone 35 and each slit 34, index dial 31 is shown, not necessarily consistent with the form of reality.In addition, Fig. 8 and Figure 10 schematically shows in order to the detection light L of autoluminescence in future mechanism 32 (its exit facet 36) detects in the state of the light area 33a light by optical mechanism 33 and reflection state easy understand that light Lr advances through the scale zone 35 (each slit 34) of index dial 31, not necessarily consistent with the form of reality and other accompanying drawings.
As shown in Figure 7, in absolute type encoder 30, clip the paired lighting means of index dial 31 32 and be set to that making it irradiate axis Ar tilts relative to rotation direction Da by the position relationship of optical mechanism 33.Above-mentioned irradiation axis Ar represents the center (optical axis) of the detection light L (with reference to Fig. 4 etc.) irradiated to the light area 33a by optical mechanism 33 through the scale zone 35 (each slit 34) of index dial 31 from the exit facet 36 of lighting means 32.In embodiment 1, the straight line that axis Ar is the center arriving the light area 33a being subject to optical mechanism 33 from the center of the exit facet 36 of lighting means 32 through the scale zone 35 (each slit 34) of index dial 31 is irradiated.As mentioned above, rotation direction Da is the direction parallel with the rotation center of index dial 31 (vertical axis Av or horizontal axis Ah).In embodiment 1, make lighting means 32 (its exit facet 36) be positioned at scale zone 35 (each slit 34 (center observed on its radial direction Dr)) than index dial 31 more by the positive side (outside when observing on radial direction Dr) of radial direction Dr, and make to be positioned at scale zone 35 (each slit 34 (center observed on its radial direction Dr)) than index dial 31 more by radial direction Dr minus side (inner side when observing on radial direction Dr) by optical mechanism 33 (its light area 33a).And then, in embodiment 1, making irradiation axis Ar relative to comprising the face of rotation direction Da with light axis direction Dp (comprising rotation direction Da and the face parallel with light axis direction Dp) becomes tilt and irradiation axis Ar is tilted relative to rotation direction Da.Above-mentioned degree of tilt is based on considering index dial 31 (its back side 31a (with reference to Figure 11 etc.)) even and if prevent the viewpoint reflecting yet arrival light area 33a as following on the reflection detection light Lr of light area 33a generation overleaf 31a from setting by the position relationship of the light area 33a of optical mechanism 33.In embodiment 1, above-mentioned degree of tilt sets as follows, namely, make lighting means 32 (exit facet 36) be positioned at than by optical mechanism 33 (light area 33a) more by the positive side of radial direction Dr, thus can prevent the reflection produced in the end of the positive side of radial direction Dr of light area 33a from detecting light Lr (following outer end reflection detects light Lre (with reference to Figure 11 etc.)) overleaf 31a reflects and arrive light area 33a.
Like this, in the absolute type encoder 30 of the embodiment of the present invention, irradiation axis Ar is tilted relative to rotation direction Da, prevents the decline of the angle accuracy of detection caused by the reflection of the detection light L be subject between the light area 33a of optical mechanism 33 and index dial 31 accordingly.Below, first, the decline of the angle accuracy of detection caused by the reflection of the detection light L be subject between the light area 33a of optical mechanism 33 and index dial 31 is described.About the decline of above-mentioned angle accuracy of detection, if make irradiation axis Ar parallel with rotation direction Da, the decline of angle accuracy of detection then can be produced in absolute type encoder 30 of the present invention, thus utilize the Reference numeral identical with the absolute type encoder 30 of embodiment 1, and mainly utilize Fig. 7 to Fig. 9 to be described.
In absolute type encoder 30, set lighting means 32 and the position relationship by optical mechanism 33 to make the irradiation axis Ar mode parallel with rotation direction Da.In this case, as shown in the double dot dash line of Fig. 7, lighting means 32 and being positioned on the Da of rotation direction by optical mechanism 33.Here, detection light L from lighting means 32 (exit facet 36) has the expansion degree (with reference to Fig. 4) of regulation, thus by the face that comprises rotation direction Da and light axis direction Dp and through the scale zone 35 (each slit 34) of index dial 31 in by the light area 33a of optical mechanism 33 light.By shown in Figure 8 for the state of this state partial enlargement.As shown in Figure 8, detect light L by the face that comprises rotation direction Da and light axis direction Dp and through the scale zone 35 (each slit 34) of index dial 31 at the light area 33a by optical mechanism 33 light.
But be subject in optical mechanism 33, usually, light area 33a has reflectivity, that is, there is the optical property reflected by light (detecting light L).For this reason, the part of the detection light L advanced to light area 33a is detected light Lr, towards index dial 31 (back side 31a) as in the 33a of light area by the reflection of reflecting.In index dial 31, the position not being formed with each slit 34 of back side 31a has reflectivity.In above-mentioned example, index dial 31 is formed by the following method, that is, carry out chromium plating to prevent overall through light to the glass plate of disc-shape, and chromium plating is removed in local, arranges each slit 34 accordingly.Chromium plating has the optical property reflected by detection light L (reflection detects light Lr too).For this reason, in index dial 31, if reflection detects the position not arranging the chromium plating of each slit 34 that light Lr marches to back side 31a, then 31a (chromium plating) can reflect above-mentioned reflection detection light Lr overleaf.So reflection detects light Lr and can again advance towards the light area 33a by optical mechanism 33, and in light area 33a light.
Here, by optical mechanism 33 (its light area 33a), only receive the detection light L arriving through each slit 34 and be subject to optical mechanism 33, read the image of each slit 34 of the scale as index dial 31 accordingly.For this reason, as shown in Figure 9, the simulated image data drawing the waveform corresponding with each slit 34 is formed by the detected value in optical mechanism 33 (its light area 33a).Accordingly, in the light area 33a being subject to optical mechanism 33, the reflection produced between above-mentioned light area 33a and index dial 31 if be received in detects light Lr (with reference to Fig. 8), then detect the light different from the image of each slit 34, thus be difficult to obtain the simulated image data drawing the waveform corresponding with each slit 34 rightly.In other words, if receive reflection at light area 33a to detect light Lr, then cause in the picture of the scale zone 35 obtained at light area 33a, make detection light L through each slit 34 and do not make the detection light L of its periphery through position between the reduction of contrast.Therefore, in absolute type encoder 30, the rotation attitude of index dial 31 can not be obtained rightly, and reduce the accuracy of detection at angle (horizontal angle, vertical angle).
Especially, in index dial 31 (its scale zone 35), each slit 34 is arranged with the interval (spacing) of regulation, and the position not thus being provided with the chromium plating of each slit 34 is also arranged (with reference to Fig. 3 etc.) with the interval (spacing) of regulation.For this reason, between light area 33a and index dial 31, light Lr can be detected to produce to reflect with state like the state class being provided with each slit 34.Thus, be subject in optical mechanism 33 (its light area 33a), as shown in the dot-and-dash line in Fig. 9, obtain the view data of the image (so-called ghost image) being detected each slit 34 of the vacation caused by light Lr by the reflection close to the waveform corresponding with each slit 34.As a result, by optical mechanism 33 (its light area 33a), the data that the view data by depicted as solid lines and the view data of being drawn by dot-and-dash line are formed by stacking are exported as detected value (simulation is by light signal Ia).The position of the appearance of this view data of being drawn by dot-and-dash line or state change according to the scale zone 35 (each slit 34) relative to lighting means 32 (its exit facet 36) and the position relationship by optical mechanism 33 (its light area 33a), are thus difficult to remove from the detected value exported (simulation is by light signal Ia).Thus, in absolute type encoder 30, the rotation attitude of index dial 31 cannot be obtained rightly, and the accuracy of detection of angle (horizontal angle, vertical angle) can be made to reduce.
For this reason, in absolute type encoder 30, consider that the position not arranging the chromium plating of each slit 34 of the back side 31a at index dial 31 arranges antireflection film.So, even if the part detecting light L reflects and detects light Lr towards index dial 31 (back side 31a) as reflection on the 33a of light area, also to prevent on index dial 31 (its back side 31a) secondary reflection again by antireflection film, thus can prevent from reflecting and detect light Lr and again arrive light area 33a by optical mechanism 33.As this antireflection film, consider and use plating chromium oxide (vapor-deposited film of chromium oxide).In plating chromium oxide, make at the composition of surface reflection own and interfere at the composition of chromium plating reflection, preventing from accordingly reflecting the generation detecting light Lr.
But, arrange this antireflection film to need, as mentioned above after formation index dial 31, to increase the operation arranging antireflection film, thus cause the increase of manufacturing process, and the increase of required material can be caused, thus cause the increase of the manufacturing cost of absolute type encoder 30.In addition, plate the expensive of chromium oxide (vapor-deposited film of chromium oxide), and finished product rate variance, thus can cause the increase of the manufacturing cost of further absolute type encoder 30.
Absolute type encoder 30 of the present invention proposes in view of above-mentioned item, without the need to arranging antireflection film, just can prevent the decline of the angle accuracy of detection caused by the reflection of the detection light L be subject between the light area 33a of optical mechanism 33 and index dial 31.In absolute type encoder 30, irradiation axis Ar is tilted relative to rotation direction Da, accordingly as shown in Figure 10, can prevent from reflecting and detect light Lr and again arrive light area 33a by optical mechanism 33.Particularly, in absolute type encoder 30, irradiation axis Ar tilts (with reference to Fig. 7) relative to comprising the face of rotation direction Da with light axis direction Dp (comprising rotation direction Da and the face parallel with light axis direction Dp), and on index dial 31, does not arrange antireflection film.For this reason, in absolute type encoder 30, if the reflection of reflecting on the 33a of light area detects the back side 31a (chromium plating) of light Lr towards index dial 31, then secondary reflection again on its back side 31a (chromium plating).But, in absolute type encoder 30, make lighting means 32 (its exit facet 36) be positioned at than by optical mechanism 33 (its light area 33a) more by the positive side of radial direction Dr, make irradiation axis Ar accordingly relative to comprising rotation direction Da and the face tilt of light axis direction Dp.For this reason, in absolute type encoder 30, the degree of tilt of axis Ar is irradiated in setting rightly, can make accordingly the reflection of secondary reflection again on the back side 31a (chromium plating) of index dial 31 detect light Lr to than light area 33a more by radial direction Dr minus side, position outside above-mentioned light area 33a advances.How the detection light L of this situation no matter caused by the diffusion of the regulation of the detection light L from exit facet 36 changes towards the angle of light area 33a incidence, similarly can occur throughout the whole region observed on the light axis direction Dp of light area 33a.This is because relative to light area 33a, face (comprising the face of radial direction Dr and light axis direction Dp) residing for the 33a of light area makes exit facet 36 be shifted to the radial direction Dr orthogonal with above-mentioned light axis direction Dp, makes irradiation axis Ar tilt accordingly.Therefore, in absolute type encoder 30, without the need to arranging antireflection film, the decline of the angle accuracy of detection caused by the reflection of the detection light L be subject between the light area 33a of optical mechanism 33 and index dial 31 also can be prevented.
Then, utilize Figure 11 irradiation axis Ar in absolute type encoder 30 to be described relative to the establishing method of the degree of tilt in the face comprising rotation direction Da and light axis direction Dp.Figure 11 is in order to easily understand setting lighting means 32 and schematically show relative to the state of the position relationship of index dial 31 (scale zone 35) by optical mechanism 33, not necessarily consistent with the form of reality and other accompanying drawings.
First, in order to set above-mentioned degree of tilt, as shown in figure 11, the inner light Le of detection of definition and outer end reflection detect light Lre.Inner detect light Le be in the detection light L that penetrates of the end (inner end positions radial direction Dr observes) of the radial direction Dr minus side of exit facet 36 from lighting means 32, towards the detection light of the end (outer end position radial direction Dr observes) of the positive side of radial direction Dr of light area 33a.In addition, outer end reflection detects light Lre and detects light Lr in the inner reflection detecting light Le of end (outer end position of observing on the radial direction Dr) reflection of the positive side of radial direction Dr of light area 33a.The inner being detected light Le relative to the angle of inclination comprising the face of rotation direction Da with light axis direction Dp (comprising rotation direction Da and the face parallel with light axis direction Dp) is set to inner incident angle θ.
In addition, when will observe on radial direction Dr, the end (inner end positions of observing on radial direction Dr) of the radial direction Dr minus side of the exit facet 36 of lighting means 32 and the interval by the end (outer end position of observing on radial direction Dr) of the positive side of radial direction Dr of the light area 33a of optical mechanism 33 are set to lighting means 32 (exit facet 36) and the radial direction distance D by optical mechanism 33 (light area 33a) lS.In addition, when will observe on the Da of rotation direction, the end (lower end position observed on the Da of rotation direction) of the rotation direction Da minus side of the exit facet 36 of lighting means 32 and the interval by the end (upper end position observed on the Da of rotation direction) of the positive side of Da, rotation direction of the light area 33a of optical mechanism 33 are set to lighting means 32 (exit facet 36) and the axis direction distance H by optical mechanism 33 (light area 33a) lS.In addition, when will observe on the Da of rotation direction, the interval of the back side 31a (chromium plating) of the light area 33a by optical mechanism 33 and the index dial 31 as reflecting surface is set to by the axis direction distance H of optical mechanism 33 (light area 33a) with index dial 31 (back side 31a) dS.By the width dimensions of light area 33a, the size dimension namely observed on the direction orthogonal with the light axis direction Dp in the 33a of light area is set to the width dimensions W of light area 33a s.When will observe on radial direction Dr, the interval of position when end (outer end position of observing on radial direction Dr) and the outer end reflection of the positive side of radial direction Dr of light area 33a detect on the face that light Lre arrives in the upper reflection of the back side 31a (chromium plating) of index dial 31 and light area 33a is parallel is set to outer end and reflects the incoming position k detecting light Lre.
In absolute type encoder 30, detect light Lre from the view point of the outer end reflection preventing from reflecting at the back side 31a (chromium plating) of index dial 31 and arrive light area 33a, setting irradiates axis Ar relative to the degree of tilt in the face comprising rotation direction Da and light axis direction Dp.This detects light Lre owing to defining outer end reflection as described above, if thus the reflection of above-mentioned outer end detects light Lre and does not arrive light area 33a, then regardless of the position reflected or direct of travel, can prevent all reflections of secondary reflection again on the back side 31a (chromium plating) of index dial 31 from detecting light Lr and arrive light area 33a.
According to above-mentioned condition, become (D lS/ H lS)=k/ (2 × H dS), reflect to prevent outer end and detect light Lre arrival light area 33a, then demand fulfillment k > W sas long as thus meet following condition.
W S＜k＝{(2×D LS×H DS)/H LS}
In addition, inner incident angle θ can represent as follows.
θ＝tan -1(D LS/H LS)
For this reason, in absolute type encoder 30, set inner incident angle θ and lighting means 32 and by optical mechanism 33 relative to the position relationship of index dial 31 (its scale zone 35) to meet above-mentioned condition, can reliably prevent from outer end from reflecting accordingly detecting light Lre arriving light area 33a.Therefore, in absolute type encoder 30, even if detect light L to be reflected (reflection detects light Lr) in the light area 33a being subject to optical mechanism 33, above-mentioned reflection detects light Lr secondary reflection again on the back side 31a (chromium plating) of index dial 31, detect position or the direct of travel of light Lr reflection regardless of above-mentioned reflection, reliably can prevent above-mentioned reflection from detecting light Lr and arrive light area 33.
Like this, as in the absolute type encoder 30 of one embodiment of the present of invention, lighting means 32 and the position relationship by optical mechanism 33 is set to make irradiation axis Ar relative to the mode that rotation direction Da tilts.For this reason, in absolute type encoder 30, even if the reflection of reflecting on the 33a of light area detects light Lr secondary reflection again on the back side 31a (chromium plating) of index dial 31, also can prevent above-mentioned reflection from detecting light Lr and arrive light area 33a.
In addition, in absolute type encoder 30, only to make irradiation axis Ar set lighting means 32 and the position relationship by optical mechanism 33 relative to the mode that rotation direction Da tilts, thus the increase of manufacturing process can not be caused, the increase of unnecessary parts is not caused yet, with arrange the situation of antireflection film at index dial 31 compared with, without the need to increasing the parts beyond manufacturing process and necessity.For this reason, in absolute type encoder 30, without the need to increasing manufacturing cost, just can prevent reflection from detecting light Lr and arriving light area 33a.
And then, in absolute type encoder 30, have with the light area 33a that linearity extends on light axis direction Dp by optical mechanism 33, and relative to comprising the face of rotation direction Da with light axis direction Dp, (comprising rotation direction Da and the face parallel with light axis direction Dp) mode of tilting sets lighting means 32 and the position relationship by optical mechanism 33 to make irradiation axis Ar.For this reason, in absolute type encoder 30, make to detect light Lr towards the direction orthogonal with light axis direction Dp in the reflection of the upper reflection of index dial 31 (its back side 31a), reflection can be made accordingly to detect light Lr advance to the position outside the 33a of light area, the degree of tilt of irradiation axis Ar thus can be made little and can reliably prevent reflection from detecting light Lr to arrive light area 33a.This is because light area 33a extends with linearity on light axis direction Dp, detect light Lr towards light axis direction Dp if thus make in the reflection of the upper reflection of index dial 31 (its back side 31a), then need correspondingly to tilt significantly with the length dimension on the light axis direction Dp of light area 33a.
In absolute type encoder 30, light axis direction Dp is made to be positioned at the direction parallel with the string of above-mentioned disc-shape by being arranged to by optical mechanism 33 relative to the index dial 31 in disc-shape.For this reason, in absolute type encoder 30, can make to detect light Lr towards the position beyond light area 33a on radial direction Dr in the reflection of the upper reflection of index dial 31 (its back side 31a), thus can reduce the degree of tilt of irradiating axis Ar relative to the face comprising rotation direction Da and light axis direction Dp, and reliably prevent reflection from detecting light Lr arrival light area 33a.In addition, in absolute type encoder 30, in order to detect the rotation attitude of the index dial 31 in disc-shape, needing the form of each slit 34 of trying to achieve scale zone 35, even if thus make irradiation axis Ar tilt, also can prevent from detecting angle having an impact.
In absolute type encoder 30, make lighting means 32 (exit facet 36) be positioned at than by optical mechanism 33 (light area 33a) more by the positive side (outside when observing on radial direction Dr) of radial direction Dr, make irradiation axis Ar accordingly relative to comprising rotation direction Da and the face tilt of light axis direction Dp.For this reason, in absolute type encoder 30, reliably can prevent reflection from detecting light Lr with simple structure and arrive light area 33a.
In absolute type encoder 30, detect light Lre in the outer end reflection that the outer end position of observing on radial direction Dr of light area 33a reflect to prevent the inner light Le that detects secondary reflection and the mode that arrives light area 33a set inner incident angle θ to set lighting means 32 and to be subject to the position relationship of optical mechanism 33 again on index dial 31.For this reason, in absolute type encoder 30, even if light L (reflection detects light Lr) reflection will be detected at the light area 33a by optical mechanism 33, and reflection detects light Lr secondary reflection again on the back side 31a (chromium plating) of index dial 31, detect position or the direct of travel of light Lr reflection regardless of reflection, reliably can prevent above-mentioned reflection from detecting light Lr and arrive light area 33a.
In absolute type encoder 30, the width dimensions W of the position based on the exit facet 36 of lighting means 32, the light area 33a by optical mechanism 33 sthe degree of tilt of irradiating axis Ar relative to the face comprising rotation direction Da and light axis direction Dp is set with position.For this reason, in absolute type encoder 30, detect the position of light L based on injection and do not want that the position making reflection detect light Lr arrival sets the degree of tilt of irradiating axis Ar, thus reliably can prevent reflection from detecting light Lr and arrive light area 33a.
In absolute type encoder 30, set lighting means 32 to make irradiation axis Ar relative to the mode that rotation direction Da tilts and by the position relationship of optical mechanism 33, thus can prevent above-mentioned paired lighting means 32 and be the complicacy that rotational symmetric position arranges multiple groups by optical mechanism 33 (testing agency) at the rotation center relative to index dial 31.For this reason, in absolute type encoder 30, can detection angles more rightly.
Because measurement mechanism 10 is equipped with absolute type encoder 30, above-mentioned each effect thus can be obtained, and can by measuring unit direction of measurement more rightly.
Therefore, in the absolute type encoder 30 of an embodiment as absolute type encoder of the present invention, the increase of manufacturing cost can be suppressed, and prevent the decline of the angle accuracy of detection caused by the reflection of the detection light L between light area 33a and index dial 31.
(embodiment 2)
Then, utilize Figure 12 the absolute type encoder 30A of embodiments of the invention 2 to be described and to be equipped with the measurement mechanism 10 of above-mentioned absolute type encoder 30A.In order to easily understand setting lighting means 32 and schematically show relative to the form of the position relationship of index dial 31 (its scale zone 35) by optical mechanism 33 in Figure 12, not necessarily consistent with the form of reality and other accompanying drawings.
The absolute type encoder 30A of above-described embodiment 2 considers that situation about being obliquely installed by optical mechanism 33 sets the example irradiating axis Ar relative to the degree of tilt in the face comprising rotation direction Da and light axis direction Dp.The basic structure of the absolute type encoder 30A of above-described embodiment 2 is identical with the absolute type encoder 30 of the above embodiments 1, thus for mutually isostructural part, mark identical Reference numeral, and description is omitted.In addition, the measurement mechanism 10 of embodiment 2 is except carrying the absolute type encoder 30A of embodiment 2, identical with embodiment 1, thus utilizes Fig. 1, and detailed.
First, in order to set above-mentioned degree of tilt, as shown in figure 12, using by optical mechanism 33 (its light area 33a) relative to index dial 31 angle of inclination, be namely set to light angle of inclination by optical mechanism 33 (light area 33a) relative to the angle of inclination of the radial direction Dr in the direction extended as index dial 31 in addition, after reflecting at light area 33a, reflected light tilt angle alpha is set at the outer end reflection detection light Lre of the upper reflection of the back side 31a (chromium plating) of index dial 31 relative to the direction angulation extended by optical mechanism 33 (its light area 33a).When will observe along the direction extended by optical mechanism 33 (its light area 33a), the end (outer end position of observing on radial direction Dr) of the positive side of radial direction Dr of light area 33a and outer end reflect detect light Lre the back side 31a (chromium plating) of index dial 31 go up reflect and arrive the face that extends inside radial direction Dr from the inner end positions of light area 33a time the interval of position be set to outer end and reflect the incoming position k ' detecting light Lre.In addition, the interval that the radial direction Dr of above-mentioned incoming position k ' observes is set to incoming position k.Here, owing to tilting by optical mechanism 33 (light area 33a), when thus will observe on the Da of rotation direction, the outer end position of light area 33a and be set to axis direction distance H as the interval of the back side 31a (chromium plating) of the index dial 31 of reflecting surface dS.
Inner incident angle θ is identical with embodiment 1, can represent as follows.
θ＝tan -1(D LS/H LS)
In addition, as described below, setting incoming position k ' and incoming position k, and set following condition.
For this reason, in absolute type encoder 30A, set inner incident angle θ and lighting means 32 in the mode meeting above-mentioned condition and be subject to optical mechanism 33 relative to the position relationship of index dial 31 (its scale zone 35), reliably can prevent outer end from reflecting accordingly and detect light Lre arrival light area 33a.Therefore, in absolute type encoder 30A, even if light L (reflection detects light Lr) reflection will be detected at the light area 33a by optical mechanism 33, and above-mentioned reflection detects light Lr secondary reflection again on the back side 31a (chromium plating) of index dial 31, detect position or the direct of travel of light Lr reflection regardless of above-mentioned reflection, reliably can prevent above-mentioned reflection from detecting light Lr and arrive light area 33a.
The structure of the absolute type encoder 30A of embodiment 2 is substantially the same with the structure of the absolute type encoder 30 of embodiment 1, thus can obtain the effect substantially the same with embodiment 1.
In addition, in the absolute type encoder 30A of embodiment 2, suppose to be subject to optical mechanism 33 (its light area 33a) to be arranged to direction (direction of existence) the inclination light angle of inclination extended relative to index dial 31 situation set the degree of tilt of irradiating axis Ar relative to the face comprising rotation direction Da and light axis direction Dp.For this reason, in absolute type encoder 30A, such as, consider by the assembling tolerance of optical mechanism 33 (its light area 33a) or manufacturing tolerance to set light angle of inclination accordingly without the need to strictly managing the precision of manufacturing process, just can prevent reflection from detecting light Lr and arriving light area 33a.Thus, in absolute type encoder 30A, the increase of manufacturing cost can be suppressed, and can prevent reflection from detecting light Lr arrival light area 33a.
Because measurement mechanism 10 (with reference to Fig. 1) is equipped with absolute type encoder 30A, above-mentioned each effect thus can be obtained, and can by measuring unit direction of measurement more rightly.
Therefore, in the absolute type encoder 30A of embodiments of the invention 2, the increase of manufacturing cost can be suppressed, and the decline of the angle accuracy of detection caused by the reflection of the detection light L between light area 33a and index dial 31 can be prevented.
In addition, in example 2, illustrate in the absolute type encoder 30 of embodiment 1 by the situation that optical mechanism 33 (its light area 33a) is arranged obliquely.But, also obliquely can arrange by optical mechanism 33 (its light area 33a) at the absolute type encoder (30B to 30F) of following embodiment 3 to embodiment 7, be not limited to the structure of the above embodiments 2.
(embodiment 3)
Then, utilize Figure 13 the absolute type encoder 30B of embodiments of the invention 3 to be described and to be equipped with the measurement mechanism 10 of above-mentioned absolute type encoder 30B.In fig. 13, in order to easily understand setting lighting means 32B and schematically show relative to the state of the position relationship of index dial 31 (its scale zone 35) by optical mechanism 33, not necessarily consistent with the form of reality and other accompanying drawings.
The absolute type encoder 30B of above-described embodiment 3 is the example that the structure of lighting means 32B is different from the absolute type encoder 30 of embodiment 1.Because the basic structure of the absolute type encoder 30B of above-described embodiment 3 is identical with the absolute type encoder 30 of the above embodiments 1, thus for identical parts, mark same Reference numeral, and description is omitted.In addition, the measurement mechanism 10 of embodiment 3 is except carrying the absolute type encoder 30B of embodiment 3, identical with embodiment 1, thus utilizes Fig. 1, and detailed.
First, the structure of the lighting means 32B of absolute type encoder 30B is described.As shown in figure 13, lighting means 32B has illuminating part 38 and reflecting part 39.Above-mentioned illuminating part 38 penetrates towards reflecting part 39 to penetrate detection light L towards the scale zone 35 of index dial 31 and detects light L, and the exit facet 36 that light-emitting area (exit facet) detects light L as injection in lighting means 32B plays a role.In embodiment 3, illuminating part 38 utilizes light emitting diode to form.
Reflecting part 39 reflects towards the scale zone 35 of index dial 31 the detection light L penetrated from illuminating part 38 (its exit facet 36).In embodiment 3, above-mentioned reflecting part 39 uses flat catoptron to form.For this reason, lighting means 32B detects light L from illuminating part 38 (exit facet 36) injection, and reflects above-mentioned detection light L at reflecting part 39 (reflecting surface), utilizes accordingly and detects the scale zone 35 that light L irradiates index dial 31.
Then, irradiation axis Ar in absolute type encoder 30B is described relative to the setting of the degree of tilt in the face comprising rotation direction Da and light axis direction Dp.In above-mentioned absolute type encoder 30B, lighting means 32B is made up of illuminating part 38 and reflecting part 39, thus uses axis direction distance H mSwith axis direction distance H lMcarry out alternative axis direction distance H lS(with reference to Figure 11).Above-mentioned axis direction distance H mSwhen expression is observed on the Da of rotation direction, the interval of the end (lower end position that upper rotation direction Da observes) of the rotation direction Da minus side of reflecting part 39 and the end (upper end position observed on the Da of rotation direction) by the positive side of Da, rotation direction of the light area 33a of optical mechanism 33.In addition, axis direction distance H lMrepresent the interval of the end (upper end position observed on the Da of rotation direction) of the end (lower end position observed on the Da of rotation direction) of rotation direction Da minus side of reflecting part 39 and the positive side of Da, rotation direction of the exit facet 36 of illuminating part 38 when observing on the Da of rotation direction.
Inner incident angle θ can represent as follows.
θ＝tan -1{D LS/(H LM+H MS)}
In addition, as described below, setting incoming position k, and set following condition.
D LS/(H LM+H MS)＝k/(2×H DS)
W S＜k＝(2×D LS×H DS)/(H LM+H MS)
For this reason, in absolute type encoder 30B, set inner incident angle θ and lighting means 32B (illuminating part 38 and reflecting part 39) in the mode meeting above-mentioned condition and by the position relationship of optical mechanism 33 relative to index dial 31 (its scale zone 35), reliably can prevent outer end from reflecting accordingly and detect light Lre arrival light area 33a.Therefore, in absolute type encoder 30B, even if light L (reflection detects light Lr) reflection will be detected at the light area 33a by optical mechanism 33, and above-mentioned reflection detects light Lr secondary reflection again on the back side 31a (chromium plating) of index dial 31, detect position or the direct of travel of light Lr reflection regardless of above-mentioned reflection, reliably can prevent above-mentioned reflection from detecting light Lr and arrive light area 33a.
The structure of the absolute type encoder 30B of embodiment 3 is substantially the same with the structure of the absolute type encoder 30 of embodiment 1, thus can obtain the effect substantially the same with embodiment 1.
In addition, in the absolute type encoder 30B of embodiment 3, make lighting means 32B detect light L from illuminating part 38 (exit facet 36) injection, and reflect at reflecting part 39, utilize accordingly and detect the scale zone 35 that light L irradiates index dial 31.In above-mentioned absolute type encoder 30B, even if when forming lighting means 32B like this, also reliably can prevent reflection from detecting light Lr with simple structure and arriving light area 33a.
In addition, in absolute type encoder 30B, make lighting means 32B be positioned at than by optical mechanism 33 more by the positive side (outside when observing on radial direction Dr) of radial direction Dr, make irradiation axis Ar accordingly relative to comprising rotation direction Da and the face tilt of light axis direction Dp.For this reason, in absolute type encoder 30B, lighting means 32B is made to detect light L from illuminating part 38 (its exit facet 36) injection, and reflect at reflecting part 39, easily can be formed as the structure with the scale zone 35 detecting light L irradiation index dial 31 accordingly, and can reliably prevent reflection detection light Lr from arriving light area 33a.This is because, if make lighting means 32B be positioned at more lean on radial direction Dr minus side (inner side when observing on radial direction Dr) than by optical mechanism 33, then in order to make the detection light L penetrated from illuminating part 38 (its exit facet 36) advance to reflecting part 39, needing setting position for guaranteeing illuminating part 38 or detecting the structure of light path of light L.
And then, in absolute type encoder 30B, lighting means 32B is had and detects light L from illuminating part 38 (its exit facet 36) injection, and reflect at reflecting part 39, irradiate the structure of the scale zone 35 of index dial 31 accordingly with detection light L.For this reason, in absolute type encoder 30B, relative to index dial 31, illuminating part 38 can be configured at the minus side of rotation direction Da and be subject to optical mechanism 33.Thus, in absolute type encoder 30B, also be configured with for drived control illuminating part 38 and the control gear 37 (with reference to Fig. 2) by optical mechanism 33 at the minus side of the rotation direction Da relative to index dial 31, can shorten illuminating part 38 or the connecting line that is connected with control gear 37 by optical mechanism 33 accordingly, and can suppress significantly for the treatment of space.In addition, in absolute type encoder 30B, the size dimension observed on the Da of rotation direction of lighting means 32B can be reduced.Therefore, in absolute type encoder 30B, can reducing portion pieces number, and easily realize miniaturization, and reliably can prevent from reflection from detecting light Lr with simple structure arriving light area 33a.
In absolute type encoder 30B, at the illuminating part 38 of the minus side configuration lighting means 32B of the rotation direction Da relative to index dial 31 with by optical mechanism 33, thus easily can be arranged at same substrate by illuminating part 38 with by optical mechanism 33.For this reason, in absolute type encoder 30B, can reducing portion pieces number, and reliably can prevent from reflection from detecting light Lr with simple structure arriving light area 33a.
Because measurement mechanism 10 (with reference to Fig. 1) is equipped with absolute type encoder 30B, above-mentioned each effect thus can be obtained, and can by measuring unit direction of measurement more rightly.
Therefore, in the absolute type encoder 30B of embodiments of the invention 3, the increase of manufacturing cost can be suppressed, and the decline of the angle accuracy of detection caused by the reflection of the detection light L between light area 33a and index dial 31 can be prevented.
(embodiment 4)
Then, utilize Figure 14 the absolute type encoder 30C of embodiments of the invention 4 to be described and to be equipped with the measurement mechanism 10 of above-mentioned absolute type encoder 30C.In fig. 14, in order to easily understand setting lighting means 32B and schematically show relative to the state of the position relationship of index dial 31 (its scale zone 35) by optical mechanism 33, not necessarily consistent with the form of reality and other accompanying drawings.
The absolute type encoder 30C of above-described embodiment 4 is reflecting part 39 facilities obliquely considering lighting means 32B, sets the example irradiating axis Ar relative to the degree of tilt in the face comprising rotation direction Da and light axis direction Dp.The basic structure of the absolute type encoder 30C of above-described embodiment 4 is identical with the absolute type encoder 30B of the above embodiments 3, thus for identical structure division, marks identical Reference numeral, and omits its detailed description.In addition, the measurement mechanism 10 of embodiment 4 is except the absolute type encoder 30C being equipped with embodiment 4, identical with embodiment 1, thus utilizes Fig. 1, and detailed.
First, in order to set above-mentioned degree of tilt, as shown in figure 14, the reflecting part 39 of lighting means 32B is set to reflection angle of inclination γ relative to the angle of inclination of the radial direction Dr in the direction extended as index dial 31 (direction of existence).
As follows, set inner incident angle θ and incoming position k, and set following condition.
H LM×tanθ+H MS×tan(θ+2γ)＝D LS
H LM×tanθ+H MS×[(tanθ+tan2γ)/{1－(tanθ×tan2γ)}]＝D LS
H LM×tan2θ－(D LS×tan2γ+H LM+H MS)×tanθ+H MS×tan2γ－D LS＝0
Here,
a＝H LM，
b＝D LS×tan2γ+H LM+H MS，
c＝H MS×tan2γ－D LS。So, above formula can be represented as follows.
tanθ＝{b+(b 2－4×a×c) 1/2}/(2×a)
Wherein, H mS× tan2 γ < D lS
Thus, k=2 × H dS× tan (θ+2 γ)
W S＜k＝2×H DS×tan(θ+2γ)
For this reason, in absolute type encoder 30C, set inner incident angle θ and lighting means 32B (illuminating part 38 and reflecting part 39) in the mode meeting above-mentioned condition and by the position relationship of optical mechanism 33 relative to index dial 31 (its scale zone 35), reliably can prevent outer end from reflecting accordingly and detect light Lre arrival light area 33a.Therefore, in absolute type encoder 30C, even if light L (reflection detects light Lr) reflection will be detected at the light area 33a by optical mechanism 33, and above-mentioned reflection detects light Lr secondary reflection again on the back side 31a (chromium plating) of index dial 31, detect position or the direct of travel of light Lr reflection regardless of above-mentioned reflection, reliably can prevent above-mentioned reflection from detecting light Lr and arrive light area 33a.
The structure of the absolute type encoder 30C of embodiment 4 is substantially the same with the structure of the absolute type encoder 30B of embodiment 3, thus can obtain the effect substantially the same with embodiment 3.
In addition, in the absolute type encoder 30C of embodiment 4, suppose that the reflecting part 39 of lighting means 32B is arranged to set the degree of tilt of irradiating axis Ar relative to the face comprising rotation direction Da and light axis direction Dp relative to the situation of direction (direction of existence) the inclined reflection angle of inclination γ of index dial 31 extension.For this reason, in absolute type encoder 30C, such as, consider that the assembling tolerance of reflecting part 39 or manufacturing tolerance set reflection angle of inclination γ, accordingly without the need to strictly managing the precision of manufacturing process, just can prevent reflection from detecting light Lr and arriving light area 33a.Thus, in absolute type encoder 30C, the increase of manufacturing cost can be suppressed, and can prevent reflection from detecting light Lr arrival light area 33a.
Because measurement mechanism 10 (with reference to Fig. 1) is equipped with absolute type encoder 30C, above-mentioned each effect thus can be obtained, and can by measuring unit direction of measurement more rightly.
Therefore, in the absolute type encoder 30C of the embodiment 4 of absolute type encoder of the present invention, the increase of manufacturing cost can be suppressed, and the decline of the angle accuracy of detection caused by the reflection of the detection light L between light area 33a and index dial 31 can be prevented.
(embodiment 5)
Then, utilize Figure 15 the absolute type encoder 30D of embodiments of the invention 5 to be described and to be equipped with the measurement mechanism 10 of absolute type encoder 30D.In fig .15, schematically show to easily understand the structure of absolute type encoder 30D, not necessarily consistent with the state of reality and other accompanying drawings.
The absolute type encoder 30D of above-described embodiment 5 is the example being provided with collimation lens 41 between lighting means 32 (its exit facet 36) and index dial 31 (its scale zone 35).The basic structure of the absolute type encoder 30D of embodiment 5 is identical with the absolute type encoder 30 of the above embodiments 1, thus for identical part, marks identical Reference numeral, and omits its detailed description.In addition, the measurement mechanism 10 of embodiment 5 is except the absolute type encoder 30D being equipped with embodiment 5, identical with embodiment 1, thus utilizes Fig. 1, and omits detailed description.
In absolute type encoder 30D, as shown in figure 15, between the exit facet 36 and the scale zone 35 of index dial 31 of lighting means 32, collimation lens 41 is provided with.The detection light L penetrated from lighting means 32 (its exit facet 36) is formed as directional light by above-mentioned collimation lens 41, and utilizes the detection light L as directional light to irradiate the scale zone 35 (each slit 34) of index dial 31.For this reason, collimation lens 41 plays a role as collimating optics mechanism.
In above-mentioned absolute type encoder 30D, identical with embodiment 1, setting irradiates axis Ar relative to the degree of tilt in the face comprising rotation direction Da and light axis direction Dp.That is, in above-mentioned absolute type encoder 30D, adopt at the lighting means 32 of the absolute type encoder 30 of embodiment 1 with by the structure being provided as the collimation lens 41 of collimating optics mechanism between optical mechanism 33 (testing agency).
For this reason, in absolute type encoder 30D, set inner incident angle θ and lighting means 32 in the same manner as example 1 and be subject to optical mechanism 33 relative to the position relationship of index dial 31 (its scale zone 35), reliably can prevent outer end from reflecting accordingly and detect light Lre arrival light area 33a.Therefore, in absolute type encoder 30D, even if light L (reflection detects light Lr) reflection will be detected at the light area 33a by optical mechanism 33, and above-mentioned reflection detects light Lr secondary reflection again on the back side 31a (chromium plating) of index dial 31, detect position or the direct of travel of light Lr reflection regardless of above-mentioned reflection, reliably can prevent above-mentioned reflection from detecting light Lr and arrive light area 33a.
Because the structure of the absolute type encoder 30D of embodiment 5 is substantially the same with the structure of the absolute type encoder 30 of embodiment 1, thus the effect substantially the same with embodiment 1 can be obtained.
In addition, in the absolute type encoder 30D of embodiment 5, the light area 33a by optical mechanism 33 no matter extended on light axis direction Dp is in the position, where on light axis direction Dp, and detection light L can be made as one man to arrive light area 33a.For this reason, in absolute type encoder 30D, angle detection can be carried out more simply, and can prevent reflection from detecting light Lr arrival light area 33a.
Because measurement mechanism 10 (with reference to Fig. 1) is equipped with absolute type encoder 30D, above-mentioned each effect thus can be obtained, and can by measuring unit direction of measurement more rightly.
Therefore, in the absolute type encoder 30D of the embodiment 5 of absolute type encoder of the present invention, the increase of manufacturing cost can be suppressed, and the decline of the angle accuracy of detection caused by the reflection of the detection light L between light area 33a and index dial 31 can be prevented.
In addition, in embodiment 5, illustrate at the lighting means 32 of the absolute type encoder 30 of embodiment 1 and by the absolute type encoder 30D being provided with the collimation lens 41 as collimating optics mechanism between optical mechanism 33 (testing agency).But, if the detection light L penetrated from lighting means 32 (its exit facet 36) is irradiated the scale zone 35 (each slit 34) of index dial 31 as directional light and be provided with collimating optics mechanism between exit facet 36 and index dial 31, then also can collimating optics mechanism (collimation lens 41) be set in the absolute type encoder of embodiment 2 to embodiment 4 (30A, 30B, 30C), be not limited to the structure of the above embodiments 5.
(embodiment 6)
Then, utilize Figure 16 the absolute type encoder 30E of embodiments of the invention 6 to be described and to be equipped with the measurement mechanism 10 of absolute type encoder 30E.In figure 16, schematically show to easily understand the structure of absolute type encoder 30E, not necessarily consistent with the form of reality and other accompanying drawings.
The basic structure of the absolute type encoder 30E of above-described embodiment 6 is identical with the absolute type encoder 30B of the above embodiments 3, thus for identical structure division, marks identical Reference numeral, and omits its detailed description.In addition, the absolute type encoder 30E of embodiment 6 is the example that the reflecting part 39E of lighting means 32E has the structure different from the lighting means 32B of the absolute type encoder 30B of embodiment 3 (with reference to Figure 13).In addition, the measurement mechanism 10 of embodiment 6 is except the absolute type encoder 30E being equipped with embodiment 6, identical with embodiment 1, thus utilizes Fig. 1, and omits detailed description.
In absolute type encoder 30E, as shown in figure 16, lighting means 32E is identical with the lighting means 32B (with reference to Figure 13) of absolute type encoder 30B, has illuminating part 38 and reflecting part 39E.In absolute type encoder 30E, reflecting part 39E has the structure different from the reflecting part 39 of absolute type encoder 30B.Above-mentioned reflecting part 39E bends to form the picture of exit facet 36 on the 33a of light area.In other words, light area 33a makes exit facet 36 and light area 33a have the position relationship of optical conjugate by reflecting part 39E as imaging surface.
In above-mentioned absolute type encoder 30E, identical with embodiment 3, setting irradiates axis Ar relative to the degree of tilt in the face comprising rotation direction Da and light axis direction Dp.That is, in above-mentioned absolute type encoder 30E, the structure that the reflecting part 39 of the lighting means 32B of the absolute type encoder 30B of embodiment 3 is bent as described above is adopted.
For this reason, in absolute type encoder 30E, identical with embodiment 3, set inner incident angle θ and lighting means 32E (illuminating part 38 and reflecting part 39E) and by the position relationship of optical mechanism 33 relative to index dial 31 (its scale zone 35), reliably can prevent outer end from reflecting accordingly and detect light Lre arrival light area 33a.Therefore, in absolute type encoder 30E, even if light L (reflection detects light Lr) reflection will be detected at the light area 33a by optical mechanism 33, and above-mentioned reflection detects light Lr secondary reflection again on the back side 31a (chromium plating) of index dial 31, detect position or the direct of travel of light Lr reflection regardless of above-mentioned reflection, reliably can prevent above-mentioned reflection from detecting light Lr and arrive light area 33a.
The structure of the absolute type encoder 30E of embodiment 6 is substantially the same with the structure of the absolute type encoder 30B of embodiment 3, thus can obtain the effect substantially the same with embodiment 3.
In addition, in the absolute type encoder 30E of embodiment 6, illuminating part 38 detects light L from exit facet 36 with consistent brightness injection, can obtain the image (simulated image data) of the scale zone 35 (its each slit 34) of the position corresponding with the rotation attitude of index dial 31 accordingly at light area 33a more rightly.For this reason, in absolute type encoder 30E, can detection angles more rightly, and can prevent from reflection from detecting light Lr arriving light area 33.
Because measurement mechanism 10 (with reference to Fig. 1) is equipped with absolute type encoder 30, above-mentioned each effect thus can be obtained, and can by measuring unit direction of measurement more rightly.
Therefore, in the absolute type encoder 30E of the embodiment 6 of absolute type encoder of the present invention, the increase of manufacturing cost can be suppressed, and the decline of the angle accuracy of detection caused by the reflection of the detection light L between light area 33a and index dial 31 can be prevented.
In addition, in embodiment 6, the absolute type encoder 30E with the structure making the reflecting part 39 of the lighting means 32B of the absolute type encoder 30B of embodiment 3 bend as described above is shown.But, if form the picture of the exit facet 36 of illuminating part 38 and make reflecting part 39 bend on the 33a of light area, then can be applicable to the absolute type encoder 30D of embodiment 4, also can adopt other structures, be not limited to the structure of the above embodiments 6.
(embodiment 7)
Then, utilize Figure 17 the absolute type encoder 30F of embodiments of the invention 7 to be described and to be equipped with the measurement mechanism 10 of absolute type encoder 30F.In fig. 17, schematically show to easily understand the structure of absolute type encoder 30F, not necessarily consistent with the form of reality and other accompanying drawings.
The absolute type encoder 30F of above-described embodiment 7 has at index dial 31 and by the structure being provided with imaging len 42 between optical mechanism 33 (light area 33a).The basic structure of the absolute type encoder 30F of embodiment 7 is identical with the absolute type encoder 30 of the above embodiments 1, thus for identical part, marks identical Reference numeral, and omits its detailed description.In addition, the measurement mechanism 10 of embodiment 7 is except the absolute type encoder 30F being equipped with embodiment 7, identical with embodiment 1, thus as shown in Figure 1, and omits detailed description.
In absolute type encoder 30F, as shown in figure 17, imaging len 42 is provided with at index dial 31 (scale zone 35) and by between optical mechanism 33 (light area 33a).Above-mentioned imaging len 42 forms the picture of the scale zone 35 (each slit 34) of index dial 31 on the 33a of light area.In other words, light area 33a as imaging surface, and makes scale zone 35 and light area 33a have the position relationship of optical conjugate by imaging len 42.For this reason, imaging len 42 plays a role as image optics mechanism.
In above-mentioned absolute type encoder 30F, set identically with embodiment 1 and irradiate axis Ar relative to comprising rotation direction Da and the degree of tilt in the face of light axis direction Dp.That is, above-mentioned absolute type encoder 30F has at the index dial 31 of the absolute type encoder 30 of embodiment 1 and by the structure being provided with the imaging len 42 as image optics mechanism between optical mechanism 33 (light area 33a).
For this reason, in absolute type encoder 30F, set inner incident angle θ and lighting means 32 in the same manner as example 1 and be subject to optical mechanism 33 relative to the position relationship of index dial 31 (its scale zone 35), reliably can prevent outer end from reflecting accordingly and detect light Lre arrival light area 33a.Therefore, in absolute type encoder 30F, even if light L (reflection detects light Lr) reflection will be detected at the light area 33a by optical mechanism 33, and above-mentioned reflection detects light Lr secondary reflection again on the back side 31a (chromium plating) of index dial 31, detect position or the direct of travel of light Lr reflection regardless of above-mentioned reflection, reliably can prevent above-mentioned reflection from detecting light Lr and arrive light area 33a.
The structure of the absolute type encoder 30F of embodiment 7 is substantially the same with the structure of the absolute type encoder 30 of embodiment 1, thus can obtain the effect substantially the same with embodiment 1.
In addition, in the absolute type encoder 30F of embodiment 7, each slit 34 in only scale zone 35 can be formed through the picture detecting the state of light L on the 33a of light area.For this reason, in absolute type encoder 30F, the image (simulated image data) of the scale zone 35 (its each slit 34) of the position corresponding with the rotation attitude of index dial 31 can be obtained more rightly at light area 33a.Thus, in absolute type encoder 30F, angle detection can be carried out more rightly, and can prevent reflection from detecting light Lr arrival light area 33a.
Owing to being equipped with absolute type encoder 30F in measurement mechanism 10 (with reference to Fig. 1), above-mentioned each effect thus can be obtained, and can by measuring unit direction of measurement more rightly.
Therefore, in the absolute type encoder 30F of embodiments of the invention 7, the increase of manufacturing cost can be suppressed, and the decline of the angle accuracy of detection caused by the reflection of the detection light L between light area 33a and index dial 31 can be prevented.
In addition, in embodiment 7, illustrate at the index dial 31 of the absolute type encoder 30 of embodiment 1 and by the absolute type encoder 30F being provided with the structure of the imaging len 42 as image optics mechanism between optical mechanism 33 (light area 33a).But, if formed on the 33a of light area scale zone 35 (its each slit 34) picture and index dial 31 with by being arranged to as optical facilities between optical mechanism 33 (light area 33a), then also can be arranged to picture optical facilities (imaging len 42) in the absolute type encoder of embodiment 2 to embodiment 5 (30A, 30B, 30C, 30D), be not limited to the structure of the above embodiments 7.
As mentioned above, absolute type encoder of the present invention (30,30A, 30B, 30C, 30D, 30E, 30F) has lighting means and by optical mechanism, above-mentioned lighting means is from exit facet irradiating and detecting light, above-mentioned reception in light area by optical mechanism to be penetrated from above-mentioned exit facet and to pass through the above-mentioned detection light of the scale zone of index dial, and above-mentioned lighting means and above-mentioned light mechanism sets to become to make from above-mentioned exit facet through above-mentioned scale zone towards the position relationship that the irradiation axis of above-mentioned light area tilts relative to the rotation direction of above-mentioned index dial.
Although be illustrated various embodiment of the present invention, only otherwise depart from purport of the present invention, such as, following distortion or change can be carried out to these embodiments, be not limited to each the above embodiments.
In each embodiment above-mentioned, make irradiation axis Ar relative to the face tilt comprising rotation direction Da and light axis direction Dp, but detect light Lr to prevent reflection and arrive light area 33a, irradiation axis Ar also can be made to tilt relative to rotation direction Da.
In each embodiment above-mentioned, make lighting means (32 etc.) be positioned at than by optical mechanism 33 more by the positive side (outside when observing on radial direction Dr) of radial direction Dr, if but make irradiation axis Ar relative to comprising rotation direction Da and the face tilt of light axis direction Dp, then also can make lighting means (32 etc.) be positioned at than by optical mechanism 33 more by radial direction Dr minus side (inner side when observing on radial direction Dr).
In each embodiment above-mentioned, single control gear 37 is set for 2 absolute type encoders 30, but also control gear 37 can be set to each absolute type encoder 30.
In each embodiment above-mentioned, absolute type encoder 30 is arranged at measurement mechanism 10, but also can utilizes and multiplely carry out angle detection by optical mechanism 33 at synchronization.

Claims (12)

1. an absolute type encoder, possesses:
Lighting means, from exit facet irradiating and detecting light; And
By optical mechanism, light area reception is utilized to penetrate from above-mentioned exit facet and have passed the above-mentioned detection light of the scale zone of index dial,
Above-mentioned lighting means and above-mentioned light mechanism sets to become to make from above-mentioned exit facet through above-mentioned scale zone towards the position relationship that the irradiation axis of above-mentioned light area tilts relative to the rotation direction of above-mentioned index dial.
2. absolute type encoder according to claim 1, wherein,
Above-mentioned lighting means has:
Illuminating part, penetrates above-mentioned detection light for the formation of above-mentioned exit facet; And
Reflecting part, reflects the above-mentioned detection light penetrated from above-mentioned illuminating part towards above-mentioned scale zone.
3. absolute type encoder according to claim 1, wherein,
Above-mentioned light area is formed in the mode of extension linearly on light axis direction,
Above-mentioned lighting means and above-mentioned light mechanism sets become to make above-mentioned irradiation axis relative to comprising above-mentioned light axis direction and the position relationship of the face tilt parallel with above-mentioned rotation direction.
4. absolute type encoder according to claim 3, wherein,
Above-mentioned index dial has disc-shape,
Above-mentioned light mechanism sets becomes to make above-mentioned light axis direction be the position relationship in the direction parallel with the string of the disc-shape for above-mentioned index dial relative to above-mentioned index dial.
5. absolute type encoder according to claim 4, wherein,
The radial direction of above-mentioned index dial is observed, and above-mentioned lighting means is positioned at than above-mentioned scale zone in the outer part,
Above-mentioned radial direction is observed, to be above-mentionedly positioned at than above-mentioned scale zone in the inner part by optical mechanism.
6. absolute type encoder according to claim 5, wherein,
At above-mentioned lighting means and above-mentioned by optical mechanism, above-mentioned detection light from the injection of the inner end positions of the above-mentioned exit facet observed at above-mentioned radial direction and towards the outer end position of the above-mentioned light area observed at above-mentioned radial direction is detected light as the inner, and the reflection that above-mentioned the inner detection light reflects towards above-mentioned index dial in above-mentioned light area is detected light and detects light as outer end reflection, set above-mentioned the inner and detect light relative to comprising above-mentioned light axis direction and the inner incident angle in the face parallel with above-mentioned rotation direction, reflect to prevent above-mentioned outer end and detect light secondary reflection and arrive above-mentioned light area again on above-mentioned index dial, set above-mentioned lighting means and the above-mentioned position relationship by optical mechanism accordingly.
7. absolute type encoder according to claim 6, wherein,
Above-mentioned lighting means has: illuminating part, penetrates above-mentioned detection light for the formation of above-mentioned exit facet; And reflecting part, the above-mentioned detection light penetrated from above-mentioned illuminating part is reflected towards above-mentioned scale zone,
Above-mentioned inner incident angle is set relative to the angle of inclination of above-mentioned index dial by additional above-mentioned reflecting part.
8. absolute type encoder according to claim 6, wherein, above-mentioned inner incident angle is set relative to the angle of inclination of above-mentioned index dial by additional above-mentioned light area.
9. absolute type encoder according to claim 1, wherein,
Also possess and be arranged between above-mentioned exit facet and above-mentioned index dial, make above-mentioned detection light become the collimating optics mechanism of directional light.
10. absolute type encoder according to claim 1, wherein,
Above-mentioned lighting means possesses: illuminating part, penetrates above-mentioned detection light for the formation of above-mentioned exit facet; And reflecting part, the above-mentioned detection light penetrated from above-mentioned illuminating part is reflected towards above-mentioned scale zone,
Above-mentioned reflecting part is bending, to form the picture of above-mentioned exit facet on above-mentioned light area.
11. absolute type encoders according to claim 1, wherein,
Also possess and be arranged at above-mentioned index dial and above-mentioned by between optical mechanism, for forming the image optics mechanism of the picture of above-mentioned scale zone on above-mentioned light area.
12. 1 kinds of measurement mechanisms, are equipped with absolute type encoder according to claim 1, and above-mentioned measurement mechanism possesses: measuring unit, can measure the Distance geometry direction of object; And control module, for carrying out drived control to above-mentioned measuring unit.
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